Air conditioning system employing steam for heating and cooling



c. M. ASHLEY 2,010,01

AIR CONDITIONING SYSTEM EMPLOYING STEAM FOR HEATING AND COOLING Aug. 6,1935.

Filed Aug. 12, 1932 3 Sheets-Sheet 1 INVENTOR. Carlyle M Ashley j mw 5wA TTORNEY 5- (1.4M. ASHLEY 2,010,001

AIR CONDITIONING SYSTEM EMPLOYING STEAM FOR HEATING AND COOLING FiledAug 12, 1952 a Sheets-Sheet 2 IN V EN TOR. Carlyle M195 leg A TTORNEYS.

6, 1935- I c. M. ASHLEY 2,010,001

AIR CONDITIONING SYSTEM EMPLOYING STEAM FOR HEATING AND COOLING FiledAug. 12, 1932 I 3 SheetsSheet 3 IN V E IN TOR. .C'a'rlyle M/lsizley BYATTORNEY plat d Au 6, 1935 2 010 001 UNITED STATES PATENT oFricE;

AIR CONDITIONING SYSTEM ELIPLOYING STEAM FOR HEATING AND COOLING.

Carlyle M. Ashley, South Orange, N. .L, assignon by mesne assignments,to Carrier Engineering Corporation, Newark, N. J., a corporation of NewYork Application August 12, 1932, Serial No. 628,558 14 Claims. (cram-9)This invention relates generally to air condiadapted to harbor a coolingmedium under sumtioning systems and more particularly to im- 'merconditions and a heating medium under provements in' methods of andapparatus for prowinter conditions, whereby air circulated in conducingboth refrigeration and heating effect utitact therewith will, under oneset of conditions,

lized in systems for dehumidifying, humidifying, be heated, and underanother set of conditions cooling; heating, as well as controlling thetembe cooled and dehumidified. perature and relative humidity, of air.Another feature of the invention provides a The general. object of theinvention is to prototally enclosed water circulation system, forcarvide an airheating and cooling system using a -rying out refrigeratiand h at processes,

10 common source of steam either for producing adapted to serve theneeds'of a boiler and asso- 10 cooling effect or for producing heatingefiect. ciatedrefrigeration and air conditioning appa- Thus, under oneset of conditions, steam will ratus, losses in water supply beingpractically be used for producing, refrigeration, whereas, gib e andresult n n yi o Purging n under another set of conditions, steam-will beations. v

used for heating purposes, thesame combination A the f atu p sforlltihzingrextleme- 15 ofapparatus being adapted to serve both pur- 1ysmall quantities of water for condensing steam I poses.- employed forproducing refrigeration, the volume Another object of .the invention isto provide a of water required being substantially only that unitaryarrangement of apparatus adapted to cool 4 quantity which the heat ofcondensation is caso and dehumidify air volumes or to heat air vol- F lfap a Which Will retflinnseries umes by employing steam from a commonsource, of condenser tubes wetted and clean, common apparatus beingemployed both for the A further object provides forsupplying waterdehumidifying'and heatingpurposes. for condensing purposes only when acontrolled Another object of the invention is to provide a supply ofsteam is being utilized to produce resystem of apparatus in combinationwith a sourcev frigerating fie w n e Pressure Wit 8 '25 of steam supplyunder a unitary control, whereby refrigeration system rises above apredetermined the steam may be used under one set of condilimit. tionsfor supplying refrigeration and under an- A further feature oftheinventio'n provides for other set of conditions for supplying heatingefutilizing totally enclosed water circuits in com- 33 feet. Thecontrol, in practice, enables the arbination with an air heating andcooling system,

grangement of apparatus to operate as a heating whereby desiredwaterlevels will be maintained and-ventilatingsystem, when increasedtemperain a steam boiler and evaporator forming part tures are desired;and may readily convert the of the system. 1 apparatus into a system'forcooling and dehu- A further feature provides for automatically midifyingair volumes, when decreased temperatransferring liquid from a sourceofsupply at one 35 tures and dehumidified atmospheric conditions pressureto a receiving means at a lower presare quired. 4 j v sure, without theintervention of mechanical A u r Object 01" the invention 15 to Providethrottling or feed control mechanism. As arecombined refri rating andheating appara suit, liquid from a'condenser is fed to an evapo- 49 wich y e operated h absolute e y i rater without the intervention or sucha device '40 e that no dangerous refrigerants are employed, as the usualexpansion valve which 18 quiet In operation, slmple 'P Afurther featureprovides for controlling a'sup 4 and capable either of heating orcooling air volply of steam for producing refrigerating exec;

umes under manual or. automatic control, and 43 whose operating costmakes for efliciency with to ng in pressure of Sam stem.

, great economy. v I A feature of the invention resides in the pmfurtherfea ure comprises a steam ejector in vision of a cont-m1 arrangementadapted to Oper combination with a boiler, whereby steam will be ate,under winter conditions, with steam pressure Supplied said for Pmducingdesired 59 between certain predetermined limits, and adaptfrigemtmgefiect only when the Steam is between ed to operate under summerconditions with the predetermined Pressure i st-eam pressure betweenpredetermined limits 4; Another feature of the invention provides forhigher pressure. g supplying steam to a steam ejector of an air con-Another feature of the invention resides in ditioning apparatus andcausing an air condithe use of a common conditioning apparatustioning-mediumtobecooled responsive to changes in heat load affectingthe atmosphere of an en- 7 closure served by the apparatus.

Another feature resides in the provision of a combined evaporator andheat exchanger thereby eliminating a pump which would otherwise beemployed to circulate the fluid for a flash evaporator through a heatexchanger.

Further features, covering advantages in structure, assembly andeconomy, as well as flexibility in operation, and assuringefiicientservice with complete safety under all operating conditions,will be more apparent from the following description of an illustrativearrangement of apparatus and controls adapted to carry out theinvention, to be read in connection with the accompanying drawings,in'which:

Fig. l is a schematic arrangement, partly in section, of an apparatusadapted to carry out the invention, generally illustrating theinterrelation of parts,

Fig. 2 illustrates diagrammatically a control arrangement to be used incombination with the apparatus of Fig. l,

Fig. 3 isan isometric fragmentary view of a .heat exchange devicemounted within a duct,

forming part of the invention, with a portion of the header being brokenaway to show the interior,

Fig. 4 is an isometric view of one of the troughs employed in the*device of Fig. 3,

Fig. 5 illustrates diagrammatically an evaporator header in combinationwith a liquid feed system for the evaporator, and a humidifying deviceabove the evaporator,

Fig. 6 is a diagrammatic view of a condenser employed as part of thecombination of Fig. 1,

Fig. '7 is a diagrammatic representation of a boiler return'trap. Y

Considering the drawings, similar designations referring to similarparts, and first with particular reference to Fig. 1, numeral lillustrates a boiler having a fire box-l2, burner pipes I, and burnersl3. While the boiler may be served with any desired fuel, for purposesof illustration, gas burners are illustrated, the burners l3 beingprovided with controlled amounts of fuel under the regulation of valveM. A flue l carried off the gases of combustion.

From the top of the boiler, pipes l6 and I1 lead to'pressure reducingnozzle l8 suitably positioned in a head casing and adapted to directfluid therefrom toward an entrance diffuser 2|. A valve I9 is providedin pipe H for controlling the admission of steam'to nozzle l8, as willbe hereinafter described. Conduit 22 connects head casing 20 with aheader 23 of a heat exchange device, designated generally by the numeral42, and shown in greater detail in Figs. 3 and 5. Entrance diffuser 2|leads into discharge diffuser 24 which, in turn, connects throughconduit25 with an inlet header 26. (Fig. 6) of condenser 21. Thecondenser 21, as shown in Fig. 6, preferably comprises an'inlet header26 and a discharge header 28 connected by a plurality of tubes 53. Thetubes preferably are provided with extended surface to promote increasedheat transfer. From the discharge header 28, a pipe 30 leads back to theboiler. A boiler return trap 3 whose operation will be hereinafterdescribed, is located below the bottom of condenser 21, but above thetop of boiler f0, and is connected to the pipe 3|! by pipe 32. 'Locatedin pipe 30 are check valves 33 and 34 between which pipe 32 joins pipe30.

The trap 3|, shown diagrammatically in Fig. '7, is of g a gravity feedtype containing a float 62 pivoted at 63, adapted to.-aetuate twovalves61 and68 in response to the movement of the float. The valves arearranged to be either fully open or fully closed and when one is openthe other will be closed. A weight 64 pivoted at 65 and attached to thearm of float 62 at point 66, by an appropriate linkage, is suitablyarranged to operate valves 61 and 68. When there is no liquid in thecasing of trap- 3| and float 62 is at its lowest. position, valve 61 isopen and valve 68 closed. As liquid fills the trap, the float rises,thereby moving weight 64 towards its dead center. When the level reachesa predetermined point, the weight passes its dead center and by gravitydrops over, thereupon causing valve 61 to close'and valve 68 to open.The movement of the weight after it passes dead center is precipitate sothat the opening and closing of valves 61 and 68 will be immediate andakin to snap action. No limitation is made to the particular form oftrap and any analogous means may be utilized for similar purposes, theparticular means described being deemed illustrative.

Pipe 35 leads from pipe It to valve 68 of the return trap.3|. Pipe 36leads from valve 61 of the trap to header 26 of condenser 21 (Fig. 6)and provides an equalizing passage therebetween, whose purpose will behereinafter described.

Heat exchanger 42 combines a plurality of functions in one apparatus andadditionally provides a simple and compact apparatus readily adaptablefor use under summer and winter con- -ing conditions will be differentlycarried on.

Thus, under summer conditions, it operates to cool and dehumidify air,whereas, in winter, it serves to heat the air. Furthermore, under summerconditions, it not only provides a cooling means directly forconditioning air passing in contact with component parts thereof, butalso serves as an evaporator for supplying a cooling medium to saidmeans. From a practical standpoint, it may be characterized as acondenser for heating air under winter operating conditions andas anevaporator for cooling air under summer operating conditions. 'Itsfunction to avoid duplication of apparatus will be apparent.

Referring more particularly to Figs. 3, 4 and 5, 42 refers to apreferred form of heat exchanger having a. single header 23. Tubes 29,preferably provided with extended surface, are bent in a U shape andhave their ends terminating in tube sheet 59 of theheader 23. As shownin Fig. 3, the ends of all U tubes in each row lie in the samehorizontal plane. Attached to the ends of the tubes of each row, is atrough 60. The trough front wall of each trough 60 (Fig. 4) hasa cut-outportion 6|. The liquid feed pipe 12 ispositioned in the top of header 23directly above the uppermost trough 60. Hence, as undersumm'er operatingconditions, a liquid fedfrom pipe 12 will fall into the upper trough andenter U tubes 29 associated therewith. The depth of cut-out portion 6|of the trough is determined by the height of liquid which it is desiredto maintain in the tubes associated with the trough. Therefore, when theuppermost'tr'ough and its associated tubes are filled to a desireddepth, additional liquid will spill over through cut-out portion 6| andflow into the trough below. Similarly, all the lower rows of tubes andtheir respective troughs will be 'U tube 29.

charged on the outside of tubes 53. A fan 52' filled to the desiredlevel. Excess liquid will spill through the cut-out portion of thelowest trough and collect in the bottom of header 23, and then.

drain or serve a function'hereinafter described. The fluid evaporated inthe tubes and trough finds a'passageway through conduit 22 connectingthe evaporator and difiuse 2|.

While the single header and U tube construction of the heat exchanger isillustratedherein, the invention is not limited thereto and, if de--sired, exchangers having oppositely disposed headers may be usedto'carry out similar tions.

Contiguous and on the same level with each row of tubes 29 in the heatexchanger, and parallel to each of troughs 60 is a pipe 3'1 (Fig. 5)extending the length of header 23. The ends of pipes 31 are mounted in aheader 69 (Fig. 5) which may be connected to steam supply pipe 35(Fig. 1) by pipe 38, under control of valve 39.

Each of pipes 31 has a series or; holes therein, a hole being providedopposite one end of each Steam issuing from each hole, as

I under winter operating conditions, is arranged tube.

end of the tube into associated-trough 60. Pipe 40, containingcheck'valve- 4|, joins the bottom to enterthe oppositely disposed openend of the Condensate willdrain out of'the other of header 23 to pipe32. Under winter operating conditions the condensate entering troughs:60,

will drain through pipe 40 back into the boiler.

Without reference to automatic features .of'

control, which will be hereinafter described, and assuming that steam.is available from .boiler I!) at a desired pressure, thatevaporatortubes 29 \of heat exchanger 42 are suitably filled tothe desired level,thatva'lve 39 (used under winter conditions) is closed, and thatyvalvel9 (used under summer conditions) is open, refrigeration operation, asdesired under summer conditons, will be efiected as followsh Steam fromboiler I0 will proceed,to nozzle l8 through pipe l6, l1 and valve I9.The steam is expanded in nozzle 45 F. Reducing the pressure atthedischarge end of the nozzle causes a corresponding reduction in pressurewithin evaporator 42, which is in communication with the outlet of thenozzle through conduit '22 and'casing 20. Consequently, heat from theair to be cooled, whose temperature is greater-than 4:5 F., will betransmitted through the tubes 29 and cause the water therein to boil:Thus, rbyextractfng the heat from the air to supply the latent heat ofevaporation to the boiling water, the air will be lowered intemperature. It is self-evident that such evaporation will produce largevolumes of vapor. To prevent building up a pressure in the tubes whichwould impede or stop evaporation, the vapor must be (removed as fastasit is produced. Its removal from tubes 29 and header 23 and throughconduit 22 is accomplished by Y the action of the jet of high velocitysteam issu-' .ing from nozzle' l8. The vapor is entrained by;

the steam andcompressed within diffusers 2| and 24 with a consequentrise in saturation temperature and pressure. The compressed mixtureisthen discharged through pipe25 into inlet header 26 and tubes 53 ofcondenser .21. For the purpose of removing the heat of-condensation,'thecondenser 21 is mounted within a tank 41. Water from a suitable sourceis fed to a spray header 48 through a pipe 49 and an aspi rator 50 underthe control of valve 5|, and'is dis- I8 to a predetermined pressure,for, example, that at which water will boil at is adapted to draw airfrom an outside source through an opening 54 in the'tank 41, through thewater sprays, over the tubes 53 and to discharge the air to theatmosphere tlu'ough the opening 55. The hot mixture of steam and vapor,at 100 F., for example, within tubes 53 its latent heat to the coolerair blowing over he outside of the will be condensed by giving tubes.The tubes are kept wet by the sprays primarily to increase the transferof heat from hot vapors to the air. By this preferredmethod. onlysuflicient water need be supplied by header 48 to keep the tubes 53.clean and wet and to take care of water losses through evaporation.

The liquid condensate from tubes 53 will drain ,into header 29 (Fig. 6)and will be returned to the boiler in a mannernow to be described. As

previously described, trap 3| is connected to line 30 between condenser21 and boiler It). An equalizing passage 36 betweentrap -3| andcondenser 21 is controlled by valve 61 in the trap;

I a passage 35 between the trap and boiler is controlled by valve 68 inthe trap. If it is assumed that trap 3| is empty, then float 62 willbein its lowest position. The valve 68 will be in closed position againstthe steam pressure in pipe 35 and valve 6! will-be retained in open.position f so'that the pressure in trap 3| will be substantially thesame as the pressure in condenser 21. Check valve 34 will be closed bythe pressure from boiler l0. Check valve 4| is also closed due to thegreater pressure in thetrap (which is substantiallythe same as condenserpressure) than exists in the evaporator. Since trap 3| andcondenser 21are substantially at the same pressure, check valve 33 will be open dueto the .head of'liquid in pipe 39; and inasmuch as trap 3| is lower thanthe condenser, condensate will fio'w by gravity from header 28 of thecondenser, through pipe 30, check ,valve 33 and pipe 32 into the trap.As the level of liquidrises in 3|; the float willrise until,.ashereinbefore explained, the weight I 64 trips, thereby closing valve 61and opening valve 68. Thereupon, steam pressure from pipe 35, will enterthe trap through valve 68 and exert a pressure on the liquid therein.Check valve 33 will immediately close and valve 4| remain closedsincetheboilerpressure is much higherthan-either condenser or evaporatorpressure. The trap and boiler'will then be under the same pressure andsince the trap is'higher than the top of the boiler, the head .of liquidwill cause check valve 34 to openandthe liquidwill flow through pipesv32 and 30 into the boiler by gravity, thereby providing for boiler feed. As the trap empties the floatwill drop, thus causing weight 64 tofall to the other side,

whereupon valve 68 will closeand valve 61 open 7 so that the cycle maybe repeate While this gravity arrangement is illustrated in connectionits attendant troubles. The operation will now be described. A well '43is provided for accumueliminates a mechanical expansion valve' withj- 23just above the uppermost trough 60. From separator 44 another pipe Hrises vertically to a predetermined height, then, as illustrated, dropsto a point well below the level' of the evaporator, proceedshorizontally and then rises to connect with the bottom of header 23. Atthe lowest point in the last piping series, and adjacent the verticalsection of pipe H leading to the bottom of header 23, is connected apipe 13 which, in practice, may parallel pipe 'H from the point ofconnection to and into header 23.

As illustrated in Fig. 5, pipes II and l3 terminate within header 23 ata height above the bottom thereof, at which it .is desired to maintainthe level of liquid in the header. The pipe -1I is exposed to theheating effect of the surrounding air to assure boiling of liquid in thevertical section of the pipe leading into header 23, while pipe 13 issuitably insulated to prevent such boiling action..

The action of returning liquid from the condenser to the evaporator isas follows: Hot condensate collecting in well 43 rises in tube 10, whichmay be insulated to prevent its cooling. As the condensate rises in pipe10, it approaches the evaporator pressure and will proceed to a point atwhich it begins to boil due to the lowered pressure. The vapor isseparated from the liquid in the separator 44. The separated liquiddrops into the trap formed by the U bend in pipe IT and then proceeds tobuild up a supply of fluid in piping 12 leading to the, point ofentrance at the top of the evaporator. The piping is so arranged that,in practice, the height of the column of liquid in pipe 10, plus thevertical height of the column of liquid in the trap portion of pipingI2, is sufiicient to balance the difference between the pressures in thecondenser and evaporator; Thus, as more water from well 43 boils andsupplies liquid to pipe 12, the balance ,will be disturbedand cause acorresponding amount to enter the evaporator; This will be carried onuntil the boiling action in the pipe 10 ceases, whereupon, the balancewill be restored and no further liquid enter the evaporator.

. The vapor from separator 44. passesinto pipe I I. v If there iss'ufiicient water in the evaporator, the level in the bottom of theheader will be above the point at which pipes H and I3 termi nate, PipesH and 13 will be filled with liquid and trap the vapor from separator 44in the pipe II. This will build up a pressure atthe separator 44 so thatthe boiling actionthere will stop. As a result, no more water will flowfrom the separator intopipe 12,:since the pressureis suflicient toretain the liquid within pipe Ill.

The vertical portions of pipes II and 13 which rise into the evaporatorshould be kept sufliclently hot so'that the liquid therein will alwaystend to boil. As a result, when the water in the evaporator boils andthe level in the bottom of header 23 decreases, the liquid in pipes IIand 13 will also tend to boil away, thereby relieving the pressure inthe line H and separator 44. As this pressure is released, boiling willagaintake place in pipe 10 and liquid allowed to flow into"line 12 andintothe evaporator until the level is again restored to the point whereliquid once again flows into pipes'll and 13 to build in line 1|sufilcient to stop further boiling in pipe 10'. I

This system normally operates under a relatively high vacuum, to wit,about 5" of mercury,

absolute pressure, in the evaporator-and 2" of mercury, absolute, in thecondenser. In practice, some leakage of air will normally occur. As aresult, if air and othergases, which make their way into the system, arenot removed, a pressure will be built up to the point where furtheroperation becomes practically impossible. To remove or purge thesegases, applicant provides aspirator 50 inwater line 49. A pipe 56 leadsto the aspirator 50 from the upper part of discharge header 2B of thecondenser, the place at which gases tend to collect (see Fig. 6). Thewater flowing through the aspirator entrains and collects these gasesand discharges them to the atmosphere with the spray water dischargedfrom header 48.

To keep the system purged of gases during the season when refrigerationis being used intermittently, a thermostatic switch 14 (Fig. 2) and asmall-heater 15 are placed in a container 16 (Figs. 1 and 6). connectedto the bottom of header 28 by tube 11. A small amount of water drainsfrom the condenser into container 16. The heat from heater '15 keepsthis water constantly boiling. The thermostatic switch 14 is set so thatit remains open as long as the temperature of the boiling liquid isbelow a predetermined point, for example, 110 F. If air collects incondenser 21, the pressure on the liquid in container 16 is increased sothat the boiling point of the liquid is thereupon increased. When itincreases beyond the predetermined point, say 110 F., the switch willclose an electrical circuit, which will laterbc described in detail, andcause water valve 5| to open, whereupon the aspirator 50 will functionto purge the condenser. 'When a suflicient vacuum is again established,the switch will open and water valve 5| close. If desired, a pressureoperated switch may be used instead of one operative responsive totemperature changes. As will be hereinafter pointed out, this circuitprovides an auxiliary operating feature, designed primarily to keep thesystem purged during those periods when refrigeration is requ red atinfrequent intervals. y

In that it is desired to operate the purge intermittently and tomaintain. the system constantly under a vacuum, as previously explained,it is self-evident that some means must be provided to close the passage56, whenever the aspirator is not functioning, to prevent air flowingback through spray header 48, aspirator 50; and pipe 56 intothecondenser 21. For this purpose, a valve I E59, similar in constructionto valve 5| 'is provided. As contemplated by applicant, valve by placinga check vvalve in pipe 56 and locating the valve 5| between theaspirator 50 and' the spray header 48. However,- with suchanarrangement; it is apparent that if the check valve should for anyreason become inoperative, the system would be flooded with water,whereas with applicants preferred arrangement, the only damage whichwould resultfrom non-operation of valve I would be the filling'of thecondenser with air. Although this would cause excessive use of water forpurging, no serious damage could be done to erence to controls whichwill be hereinafter described, valveIil will be retained closed andvalve 39 open. Steam from boiler I will flow through pipe 'I6, pipes35and 38, valve 39 and header 69 (Fig. into pipes 31. The steamwill bedischarged from pipes 31 through the holes therein, ashereinbefore-described. These holes are arranged to direct the steamtoward one end of each U tube 29. As may benoted by reference to Fig. 5,the holes in tubes 31 are so positionedjhat the steam will'enter tubes29-over the upper edges of the troughs. The tubes will thereupon beheated and condensate will drain through the opposite ends, fill thetroughs and collect in the bottom of header 23. Pipe 4.0 leading fromthe bottom of header 23 will fill and open check valve 4I, close valve33, and open valve 34, whereupon the water will drain by gravity back tothe boiler. This is due to the fact that the pressures in the boiler andheat exchanger are substantially the same and the head of liquid will besufficient to cause the flow back to'the boiler at the lower level.

An extension of pipe 35 is shown which may lead to radiators ofconventional design located in a garage, servants quarters or otherplaces which cannot be heated practically from a central heat exchanger.

Althoughit is desired, under winter operating conditions, to air bindthe condenser, diffusers and the head casing 20 to prevent the heatingof these elements, it is also desired to keep the heat exchanger freefrom air so t at it may function properly. For this purpose,athermostatic air vent I10, generally well known in the heating art, isconnected through pipe "I with condensate drain 40, and subjected to thehot steam vapors in 42. As long as the hot steam can afiect thethermostatic element of the vent I10, the vent will remain closed tothe-atmosphere. However,

as air collects in the pipe "I and vent I the I thermostatic elementcools o'if; opens a valve' and allows the steam to force the air out ofthe heat exchanger. It is apparent, from a foregoing sec-( tion of thisspecification, that underv summer con- 1 ditions, the vent I10 would beopen to the atmosphere at alLtimes. To prevent air working its way intothe system'through the'vent I10 under summer operating conditions), a,check valve I12 is placed in the line "I. When the vent I 10 is openand the heat exchanger 42 is'u'nder vac!- uum, atmospheric pressure willkeep the check valve tightly closed. If any radiators are connectedonthe extension of line 35, the possibility of which was previouslypointed out, it is neces sary to insert a two-way thermostatic air ventI13 in pipe I1. This. valve is similar'to I10 but is arranged to breakanyvacu'um existing in the system under winter operating conditions aswell as vent air as desired. Its operation is similar 'to vent I69,hence, no further description is thought necessary. a

Forthe' purpose ofcontrolling the relative humidity.,,of the air'duringthe heating season, a pan I60 (Figs. 1 and 5), containing a variableamount of water, as will be hereinafter described,

is placed in the duct 51, preferably above the heat exchanger device 42,and is supplied with heat from any desired source, as, forexample, thesteampipes I65. A hygrostatic switch I64, located in the space to beconditioned and responding to changes in relative humidity of the air.therein, is-adapted to close an electrical circuit and vaporize thewater, and similarly, there will be an appreciable interval before thehygrostat I64 will'respond to the increased humidity. A

valve. small enough to supply .water at just the rate at which it couldbe evaporated by the heat and absorbed by the air would not be verypractical. To prevent flooding, and more important, to prevent overhumidification, a,float'. l63 re- I66, is placed in the electricalcircuit, (to bejdescribed in detail later) inseries with the hygrostatI64. The floatI63 will operate switch I66 to sponding to changes in thelevel of water in pan 7' .I60, and adapted to operate an (electricalswitch break the electrical circuit, Hence, closing the valve I62 (as bya spring) as the'level in pan I60 rises to a certain inaximum. As thewater evaporates, the level in I 60 will decrease and the float willfall. At a certain minimum, the float will close switch, I66, and ifhygrostat I64 is still closed, the circuit will again be closed to openthe water valve I62 to supply water to pan I60.

Obviously, the float I63 in its preferred form,

will be set to operate between close limits, hence, supplying only asmall quantity of water to the pan I60 before it operates to close valveI62. The float I63 inmany cases will operate to open and close watervalve I62 several times before the hygrostat I64 operates, indicating,of course, that further humidification is unnecessary. 'In this manner,a very fine and smooth control of humidity is assured.

. The heat exchanger 42 is mounted within a duct 51 (Figs. 1 and 3) sothat. air from fan 58 serving the system will be forced over the tubes20 and be heated or cooled, depending upon whether the heating orrefrigeration process. is

" being carried on; After being heated or cooled by contact with tubes29, the air then proceeds- .through 'duct 51 to the space to beconditioned.

When air is being cooled by exchanger 42, as

under summer requirements, moisture will be condensed from the air.

To prevent, rusting and other deteriorative eflects, eliminators I14 areprovided in duct 51 below the heat exchanger. The eliminators I14(Fig. 1) comprise a series ofarcuate metal plates extending across theduct 51.- The lower edge ofeach plate is turned upwards, thereby forminga gutter. The plates are preferably mounted on an angle with thehorizontal, so that moisture deposited on the ,tubes 29 may fall,collect in. the gutters of the eliminator plates and drain to anydesired common source. 1 Applicant's system has been-designed to operatebetween certain pressure limits un'der winter operating conditions, as,for example, between 0 and 4 pounds per square inch, and to operateunder contacts II9 the operation secondary winding summer operatingconditions, when steam is employed for refrigeration purposes, atpressures between different limits, as for example, between 10 and 14pounds per square inch. This differential in pressure limits has beenutilized by applicant in the design of a control arrangement adapted tocomplete the system and make it entirely safe in operation as well asautomatic in its function.

Referring to Figs. 1 and 2, numeral I8 represents a duplex switchmounted on boiler I0 by pipes and 8|. The switch is of the type in whichan electrical connection is made when the pressure in boiler I0 dropsto' a certain low pressure, for example, ten pounds per square inchgauge pressure, and is broken when the pressure rises to an upper limit,for example fourteen pounds per square inch. It is evident that theswitch could be set to operate within any desired pressure range, Thedevice, therefore, operates responsive to changing boiler pressures. Italso operates responsive to changes in water level within the boiler,thus carrying out a second function. A float, not shown, in the body ofdevice I8 is adapted to open the electrical connection shown in Fig. 2when the level of water in boiler I0 drops below a predetermined point.This connection remains open until the boiler is again filled to a safelevel, as through inlet I58 leading from a desired source of supply.Sight glass I9 is mounted on the device to give a visual indication ofthe liquid level in boiler I0. Another pressure switch 82 is mounted onand connected to the boiler by a pipe 83. This switch 82 is adapted tooperate three electrical contacts I43, I I9 and I20. Contacts I I9 and I20 close andcontacts I43 open when a pressure, for example, of 4 poundsper square inch is attained in the boiler. When the pressure drops to 0pounds per square inch, contacts I I9 and I20 open and contacts I43close. Contacts I43 control the supply of fuel to the burners duringwinter operation, contacts I20 the operation of the air circulation fanmotor and of the condenser fan motor. A third pressure switch 84 ismounted on and connected to boiler I0 by pipe 85 and operates responsiveto boiler pressure to control an electrical contact arm I26. When theboiler pressure rises, for example, to 13 pounds per square inch, armI26 will make a connection with contact 121 to open steam valve I9,admitting steam from boiler to nozzle I8. The arm will remain in contactuntil the pressure drops, for example, to 9 pounds per square inch whenit willbreak contact I21 and make another connection at contact I32 toclose valve I9.

Referring to Fig. 2, transformer 86 has its primary winding 8! across asource of 110 V. current. This line includes a two-pole hand. switch 88and thermal switches 89 and 90. The closing of switch 88 energizesprimary winding 81, making current available to the secondary circuit,whose operation will hereinafter be described.

A five-pole double throw switch, generally designated. 9|, enablespositive control of the sys-. tem by an unskilled operative,'under,winter and summer conditions.

'When the center and bottom row of contacts are connected, the systemwill function under winter controLwhereas if the center and top row ofcontacts are connected, the system will be under summer control. v

By reference to Fig. 2, it will be noted that I00 of transformer 881sarranged to give two low voltages, in practice, prefadjacent valve I 4,

transformer 86. The. winter/summer switch 9| isclosedon the summer side,with the center terminals connected to the upper terminals. The closingof switch 9| completes a circuit across the 110 V. line including leads92, thermal switch I38, leads 93, contacts 94 and 95 of switch 9|. lead98, heating element I5 and lead 91 back to switch 88. Element I5thereupon heats up and starts the water boiling in its container I6,connected to discharge header 28 of the condenser as previouslyvdescribed. If the system has been inoperative for some time, thecondenser will be filled with extraneous gases andthe boilingtemperature of the water in container I6 will be high enough to actuatecontact arm 98 of thermostat I4 to make contact at 99, thereuponcompleting the following circuit: Secondary winding I00, lead I0 I,contact arm 98, contacts 99, lead I02, contact I03 and I04 of switch 9I, condenser water valve 5| and valve I59 in parallel therewith, andlead I05 back to secondary winding I00. The completion of this circuitwill cause valve BI and valve I89 to open simultaneously, whereupon,aspirator 5.0 will start purging the condenser. When the action of theaspirator has .produced a s'ufllcient vaccum in the system so that thetemperature of the boiling liquid in container "I8 drops to apredetermined point, arm 98 will thereby shutting ofi water valve 5|,and simultaneously closing valve I89. The arm 98 is so arranged that itmakes contact either. at 99 or at I05, and it always is in one of thesetwo positions. Assuming that thermostaticswitch I01,- located in thespace to be conditioned, is closed, thus indicating that the spacerequires refrigeration, and assuming that the burner pilot, 'not opensvalve I4 to admit fuel to burners I8 which I will be ignited bythepilot; thereupon supplying heat to boiler I0. when valve I4. opens, toallow fuel to proceed to the burners, amechanical connection'closeslimitswitch II4, shown on Fig. 2

whereupon the. following circult is closed: Secondary switch II4, leadsH5 and I02, contacts I03 and I04 of switch 9|, condenser water valve 5|,valve I89, and lead. I09 back to secondary winding I00. This causesvalves 5| and I09 to open, thereby allowing water to flow throughaspirator50 and spray header 48-onto the condenser tubes. After- .theburners have been in operation awhile and 'the pressure in boiler I0reaches 4 pounds per lead I09, contacts IIO of 10 pounds per squarebreak its contact at 99, 1

winding I90, lead IOI,

' square inch, pressure switch 82 operates to close connections H9 andI20, completing acircuit including the 110 volt line, lead 92, then inparallel through leads 93 and H6 and their respective contacts 94, 95and I11, II8, respective switches H9 and I20, motor|2| of fan 52andmotor I22 of fan 58 respectively, leads I23 and I24 respectively andback to starting point through lead I25. This will cause airconditioning fan 58 and condenser fan 52 to operate.

When the pressure in the boiler reaches 13 pounds per square inch,contact arm I26 of pressure switch 04 moves to make contact at I21,closing the following circuit: 20 V. terminal of secondary winding I00,leads II3, I28 and I29, contact arm I26,-contact I21, winding I30 ofvalve I9, and lead I3I back to secondary winding I00. The energizationof winding I30 opens steam valve I9 and allows steam to enter nozzle I8,thereupon starting up the cooling or refrigeration action in the heatexchanger 42 which then functions as an evaporator, as previouslydescribed. If the pressure in boiler I rises to 14 pounds per squareinch pressure switch 19 will open, thereupon breaking the circuitforoperat-- ing fuel valve I4, which will then close,'as by a spring. Theclosingof valve I4 causes switch I I4 to open, as by a mechanicallinkage arrangement, whereupon the c'rcuit including water valve andvalve I69 will e broken and the valve caused to close. However, steamvalve I9 will still remain open and continue to supply steam to nozzleI8. The consumption of steam, however, is normally relatively large withrespect to the reserve capacity of the boiler. Hence, if room thermostatI01 is still demanding further; cooling, boiler pressure will soon dropto pounds per square required, the fuel valve will remain closed andthepressure in boiler I0 continue to drop. When the pressure drops to 9pounds per square inch, arm I20 of pressure switch 84 moves to makecontact at I32 closing a circuit including 20 V. terminal of secondarywinding I00, leads II3, I29,

I29, arm I26, contact I32, winding I33 of valve I9 and lead I3I back tothe transformer. The energization of winding I33 causes valve I9 toclose, therefore cutting off the steam to nozzle I8.

With steam valve I9 and fuel valve I4 closed, the

pressure in boiler I0 will drop slowly until at 0 pounds per squareinch, contacts 9 and I20 of pressure switch 82 will be broken therebystopping motors |2I and I 22 operating respectively condenser fan 52 andair conditioning'fan 58. If it is desirable to keep the air conditioningfan 58 operating constantly, to insureeirculation of airin theconditioned space, contacts I20 may be short circuited through leads I34and I35 by clos-' of switch 9| from the upper to the lower set ofcontacts. If the system has been inoperative during the intermediateseason when neither valve 39 will thereupon close.

heating nor cooling is required,- air will have leaked into the system.This fact is taker-radvantage of,as previously pointed out, under winterconditions to air bind condenser 21 and diffusers 2| and 24 to preventtheir heating. The

shift of switch 9| to the lower contacts retains valves 5| and I69closed so that the system can n-otxbe purged by the aspirator, nor canthe air .escapefrom the'condenser because of valve I69.

The closing of switch 9| will cause a circuit to be completed includingsecondary winding I00,

lead IOI, arm 98 of thermostat 14,- contact .99.,

son, thermostat I01 is short circuite'd through leads MI, 109, andcontacts I42, IIB of winter/summer switch'9l. The completion of thiscircuit will open fuel valve I4 to cause the production of steam inboiler I0. When the boiler pressure rises to 4 pounds per square inch,switch I43 will open, thereby closing the fuel valve, and 'when theboiler pressure is reduced to zero, the

fuel valve will again open, thus; steam for heating is constantlyavailable.

A thermostat, generally designated I44, located in the space to beheated, controls the operation of motor -I22 for air conditioning fan 58and steam valve 39. Assuming the space requires heating, then movablearm I45 of thermostat I44 will make contact at I46, thereby completing acircuiirincluding leads IN and 141, contacts I48 and I49 of switch 9|,lead I50, arm |45,'eontact I46, winding I52, and leads I28 and H3 to the20 V. contact of secondary winding I00. Steam valve .39, operativeresponsive tothe completion of this circuit, will thereupon .open andadmit steam to the exchange device 42, which now serves as a heatradiator. If the space becomes too, warm, the arm-I will make contact atI53,

thereby closing a circuit including leads IM and I41, contacts I48 andI49, lead I59; arm I45, contact I53, winding I54, leads I28 and H3 tothe 20 V. contact of'secondary winding I00. Steam While two circuits areprovided for positively opening and closing valves suchas I9 and 39, itis obvious that a spring type valve may be employed whereby a circuitwill be completed for operating the valve in one direction, the valvebeing operated in the other direction by spring action upon the breaking of the circuit.

When valve 39 is opened, as previously described, its operation by anysuitable means causes arm I55 to close a circuit, including the I56, armI55, lead I5I, motor I22 of the air conditioning fan 58 and leads I24and I25 back to the 110 V. line, leads 92 and H6, contacts H1 andhumidifier to absorb water vapor. 'As previously shown, the fan 58,under winter operating conditions, can only be running when the steamvalve is open. Further, when the steam valve is open, the contact I43 ofpressure switch 82 will nor- -mally be closed, and the fuel valve open.The

humidifier circuit is placed in series with the contact I43 of pressureswitch 82, so that it will be inoperative unless this contact is closed.If it is assumed that contact I43 is closed and that there is no waterin tank I60, then contact I66 will be closed, and, assuming further thatthe hygrostatic switch I64 is closed, indicating that humidification isrequired, a circuit will be completed including the V. terminal ofsecondary winding I00, lead II3, pressure switch I8 (closed below 10pounds per square inch steam pressure), contact I43, lead I09, contactsI10 and I42 of switch 9|, lead I4I, pilot switch I08, lead I6'I,

hygrostatic switch I64, contacts I66, operating responsive to float I63,water valve I62, leads I68 and IOI back to the secondary winding I00.

Energizing this circuit causes the-water valve I62 to open and supplywater to the humidifier pan I60. As was explained before, the floatI63,-responding to the water level in humidifier pan I60, will opencontacts I66, when the water level reaches a predetermined maximum,thereby breaking the circuit. Valve I62, willbe arranged 'to close underthe action of a spring or weight.

As the level decreases, the float will close contacts I66 at apredetermined minimum, thereby again closing the circuit and openingvalve I62. It will be understood that this cycle maybe repeated severaltimes before the hygrostatic switch I64 operates to break the circuit.It is apparent that if the pressure switch 82 operates condenser to theevaporator, and. various other.

matter herein disclosed but not claimed.

Since certain changes in carrying out the above process and in theconstructions set forth, which embody the invention may-be made withoutdeparting from its scope, it is intended that all matter contained intheabove description or shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

Having described my invention, what I claim as new and desire to secureby Letters Patent of the United- States, is:

1. An air conditioning apparatus of the character described, comprisinga source of steam, a. first path for steam from said source, and. meansincluding a steam ejector in communication with a heat exchange devicewherebysteam supplied ratus serving said unit for increasing thetemperature thereof under winter operating conditions.

3. An air heating and cooling system, comprising means for supplyingsteam to an ejector, a heat transfer unit in communication with theejector, the dischargeof steam within the ejector.

being adapted to evaporate liquid within the unit to cause a reductionin temperature within the unit and means for supplying steam directly tthe unit,to cause a heating thereof.

4. In a system for heating and cooling enclosures, a source of steam,steam ejector apparatus in communication with a heat transfer unit,means for discharging air over said unit, means operative-responsive tosteam pressure between certain predetermined limits for admitting steamto the ejector apparatus whereby the unit will be cooled by theevaporation of liquid therein, and means operative responsive to changesintemperature within the enclosure for admitting steam to the unit tocause a heating thereof.

5. In an air conditioning system, a heat.transfer device, a fan fordischarging air over said device, a steam ejector in communication withsaid device, means for supplying steam to said ejector whereby liquidwithin said device will be evaporated and said device will be cooled,and other means for admitting steam directly to said device whereby itwill be heated.

6. In an air conditioning system, a heat transfer device, a steamejector in open communication with said device, a source of steam, meansfor admitting steam from said source to said ejector whereby a liquidwithin said device will be evaporated to cool the device, means foradmitting steam directly to said device whereby the device will beheated, and a fan for discharging cation with said unit, means forsupplying steam to said ejector whereby the liquid in the unit will beevaporated and the unit cooled, other means for supplying steam into theunit whereby the unit will be heated, and a fan for discharging air oversaid unit.

9. An air heating and cooling system comprising a source of steam, aheat transfer unit, a steam ejector in communication with the unit,means operative responsive to steam pressure within certain limits foradmitting steam to said ejector' whereby liquid in the unit incommunication therewith will be evaporated and the unit cooled, andother means for admitting steam to said unit for causing a heatingthereof.

10.'In a system for heating and cooling an enclosure, a source of steam,a heat transfer unit, a steam ejector in communication witlr'said unit,means for admitting steam at certain pressures to said ejector, meansfor admitting steam at other pressures directly to said unit, theadmission of steam to said ejector being adapted to cause evaporation ofliquidwithin said unit to cool said unit, the admission ofsteam'directly to said unit being adapted to cause a heating of theunit, and a ianfor discharging air over the sur-' faces of said unit.

11. In a heating and cooling system, a heat transfer device, including aplurality of tubes, means for retaining .a desired quantity of liquid inthe bottom of said tubes, a pump in communication with said device, saidpump being adapted to cause evaporation of said liquid within saidtubes, thereby to cool said device, means for admitting vapor directlyto said device to cause a heating thereof, and means for-discharging airover the surfaces of said device.

12. In an air heating and cooling system, a heat transfer device,including a receptacle for fluid means for retaining a volume of liquidin said receptacle, a means in communication with said device forreducing the pressure therein under certain conditions, means fordischarging a vapor within said device under other conditions, and meansfor passing air over the surfaces of said device.

13. In a heating, and cooling system, a heat transfer device, includinga plurality of tubes, means for retaining a desired quantity of water inthe bottom of the tubes of said device, a steam ejector in communicationwith said device, a source of steam, means for admitting steam from saidsource to said ejector whereby a portion of the water in said devicewill be evaporated and the device cooled, 'other means for admittingsteam from said source directly to said device, whereby the device willbe heated, and means for discharging air over the surfaces of saiddevice. 14. An air conditioning apparatus of the character described,comprising a source of steam,- a first path for steam from said source,and means including a steam ejector in communication with a heatexchange device whereby steam supplied ing steam from said source,thereby to produce 20 the device.

heating efiect within CARLYLE M. ASHLEY.

CERTIFICATE or conmzcr org.

Patent No. 2,019,001 August 6. 1935.

CARLYLE M'. ASHLEY.

' It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 3,first column, line 7, for' "diffuse" read diffuser; page 5, firstcolumn, line 58. after "170" insert the parenthesis' mark page 9, li'rstcolumn, line 15, claim 12, for "fluid" read liquid; and line 16,s'trilteout the article "a"; and that the said Letters Patent should beread with these corrections therein that the same may conform to therecord of the case in the Patent Office.

Signed and sealed this 12th day of November, A. D. 1935.

Leslie Frazer (Seal) .Acting Commissioner of Patents.

